In the study of species-rich tropical rainforests, a central theme focuses on factors that determine diversity and patterns of species assemblages. In this context, the role of local versus regional patterns of species richness in tropical assemblages is little understood (see Condit et al. 2002; Hill & Hamer 2004). Because of the importance of environmental variation in organizing animal communities and populations (Kneitel & Chase 2004), the large variability inherent to undisturbed rainforests provides a wide range of challenges and opportunities for basic research approaches at the same time. In heterogeneous landscapes, organisms are not evenly distributed. Habitat selection combined with uneven resource availability in space and time leads to clumped distributions of animals in relation to favourable habitat patches (e.g. Morris 2003; Morales et al. 2004). In terms of basic and applied conservation research, it is important to understand not only how species are organised in species-rich assemblages in undisturbed forests, but also how conversion and loss of undisturbed rainforest affects those assemblages. In this context, with a better understanding how and to which degree animals are linked to certain features of pristine forests and how they respond to patch dynamics, we may be able to predict their responses to habitat conversion such as logging. In return, by understanding effects of logging on species assemblages, the impact of environmental variation in structuring natural assemblages may become more apparent. A framework for examining the effects of environmental variability on the structure and organisation of animal communities is given by the spacing and diversity of tropical trees, as they comprise the most fundamental structuring and resource-providing component of the ecosystem. For example, more than 3,000 tree species (with up to 300 species accumulating on a single hectare) have been recorded for the rainforests in Borneo, one of the ‘hot spot’ areas in terms of biodiversity (MacKinnon 1996; Myers 2000). Markedly, the Borneo lowlands ecoregion contain more vascular plant species than any other ecoregion on earth with approximately 10,000 species (Kier et al. 2005). The high diversity of trees is composed of a range of common species with a wide and rather even distribution accompanied by trees that occur at low densities and with a scattered distribution. Many trees, especially rare species, are not evenly distributed but spatially aggregated (Condit et al. 2000). Additionally, rainforests are frequently perturbed by local 10 SUMMARY disturbances, such as treefalls that briefly interrupt the closed canopy and homogenous forest face (Denslow 1995; Schnitzer & Carson 2001). Including those natural disturbances, diverse tropical forests are made up of patches at different successional stages, ranging from recent treefall gaps covered with pioneer vegetation to closed old-growth stands of trees (Hubbell et al. 1999; Molino & Sabatier 2001). Given the high diversity of trees in tropical forests, we expect to find adaptations to this ecological variability among animals that are common and widespread. In comparison, we expect to find specializations of animals on particular, patchily distributed resources among less common, locally aggregated species. Logging of a tropical rainforest inevitably changes the composition of its flora and fauna. Whereas selective logging of commercially valuable trees may mimic numerous natural treefalls, extensive logging with clear-cutting of areas disrupts the original forest structure. In partially logged forests, old-growth trees are largely replaced by pioneering trees and other fast-growing plants. Overall, logging affects distribution and availability of resources as well as structural components of the forests. Consequently, the response of wildlife to those changes caused by logging depends on the extent of logging, forest age, and the type of animal species in question (Uuttera et al. 2000; DeWalt et al. 2003). Features of logged forest differ with logging practice (e.g. conventional techniques versus lower impact techniques). With time, some ecosystem characteristics of previously logged forests may eventually converge to old-growth forest patterns (see Sist et al. 2003). Generally, secondary forests that have not been clear-cut may feature disturbance regimes similar to primary forest, but mostly on a much larger scale, that is with many more gaps per area than in undisturbed forests. Thus, the spatial distribution of animals in an undisturbed rainforest, particularly their use of gaps, may indicate their tolerance towards logging. Conversely, logged forests provide experimental settings that offer a broad range of different patch sizes and qualities (e.g. extent of gap features), allowing comparison of species’ tolerances to contrasting environments. Most often, logging results in a reduction of species numbers, while others do well in secondary forests (e.g. Heydon & Bulloh 1997; Malcolm & Ray 2000; Davis et al. 2001; Floren & Linsenmair 2001). It has, however, proven difficult to predict which species will tolerate logging at particular sites and why they do so. In logged rainforests, there is a lower survival probability for those species that are not able to cope with changes in resource availability, abiotic factors, predators, parasites, or competitors. Nevertheless, in spite of this important topic, empirical data remain rare.